[Clap135]

Originally Posted by KennyPowers

Right on.

What I will add is

-JB people apparently base this on blind faith, and statements like "nobody has blown their engine" and we have "thousands of happy owners"

-all other tuners including Cobb decrease the set maximum timing values from the stock 335i baseline values because the requested boost/load of the tune will result in an elevated occurance of knock sensor related events in which timing is dropped (which most equate with minor knock events)

-this same relationship (higher boost/load resulting in lower ignition timing) is seen on all other platforms, and is practiced on the 335is as well by BMW

ALL that being said, I find this to be bad news for jb3 owners, and is the reason I didnt and would not buy one. Some may prefer to take their chances, I dont.

I am a scientist by trade, and correlations and analogs are very important in my business. I do not blindly ignore them.

Im a scientist by trade to, my life revovles around excel and numbers after the field data is completed. You simply cannot ignore evidence and brush it off.

[e90injrz]

Bump for more info








Jk.

[RambleJ]

Hell, I'll still buy a JB4 and so will hundreds/thousands of people....
/thread

[Clap135]

Originally Posted by RambleJ

Hell, I'll still buy a JB4 and so will hundreds/thousands of people....
/thread

No one here is saying you should buy another tune. If you are ok with being the only one that relies on the knock sensor 100 percent of time. Then more power to you.

[ExpensiveTaste]

Originally Posted by Clap135

No one here is saying you should buy another tune. If you are ok with being the only one that relies on the knock sensor 100 percent of time. Then more power to you.

Well that's any tune using autotuning...

[Jeff@TopGearSolutions]

Originally Posted by ExpensiveTaste

Well that's any tune using autotuning...

Autotuning is a broard terminology.

Be more specific? For instance PROcedes autotuning does not simply use the knock sensor to reduce timing everytime it may in fact knock. There is plenty more to the equation.

For specifics, your better off asking Shiv. But I disagree with that statement at the end of the day.

[roninsoldier83]

Originally Posted by Clap135

You have seen this difference because you were monitoring ignition on the cylinder that wasnt dropping timing the most.
There is also the case of over sensative knock sensors and something called phantom knock wich is not even cause by the engiens knocking.

Good theory there buddy, although unfortunately, those cars only have 1 knock sensor, and last I checked, under Open Loop mapping, timing values on those cars are across the board. Besides, even if they could change timing values per cylinder (like N54's can) under open loop, there wouldn't be much of a point, they only have 1 knock sensor (placed closest to cylinders 3 & 4 on Subies), so there's no way to monitor knock per cylinder, they don't have any sort of EGT built in (much less on a per cylinder or at least per bank basis), no wideband O2 to speak of (cheap narrowband O2 FTL ), so the ECU can't even read a full range of AFR's, much less on a per cylinder basis... so even if the ECU could alter timing on a per cylinder basis under full load/OL fuel maps, it can't monitor individual cylinders, making it kind of pointless.

Don't take my work for it though, feel free to check it out for yourself :
http://www.openecu.org/index.php?title=Main_Page
http://www.romraider.com/

I'm very familiar with phantom knock, although I won't lie, for such occurrences back in the day I was always jealous of EVO's as they actually had a parameter to adjust knock sensor sensitivity, would have helped with a couple Subie's I played with back in the day.

Either way, knock count can be an arbitrary number and is based on the software you're running to decipher it. For instance, on an EVO, last I checked the knock value number seen when logging via Cobb's ATR is actually: Cobb number / .35 = actual knock count. Using an older (outdated) piggy on those cars like the PowerFC would display values of ~20 counts on occasion after tuned, which was considered fairly normal, and nothing to worry about until it hit around a count of ~60 or so. Either way, it's not always a 1 KC=1 degree of timing pulled. The figure can be arbitrary.

Not that it really matters, or is any way shape, or form related to this thread

Just my $.02

[Clap135]

bmw doesnt have 6 knocks sensors, but yet you can monitor all six cylinders.
I know the number is whatever the tune spits out. But generally the rules is that for each count, you drop 1 degree

[roninsoldier83]

Originally Posted by JPSlick

Yes I'm aware, as well as the back cylinders liking to go lean.

Yeah, the combo of unequal length runners, unequal length fuel lines and turbo placement is not very friendly to the back cylinders haha (particularly #4).

[Forcefed3]

So if the timing isnt correct meth couldnt even help the knock, correct?

[Clap135]

Originally Posted by gbreeE90

So if the timing isnt correct meth couldnt even help the knock, correct?

Meth will help you reach the max preset timing curve wihtout knocking....assuming you keep it reasonable with boost levels.

[Jeff@TopGearSolutions]

Originally Posted by roninsoldier83

Yeah, the combo of unequal length runners, unequal length fuel lines and turbo placement is not very friendly to the back cylinders haha (particularly #4).

Unfortunately the = length aftermarket headers ruin the subie sound we have come to love. (a little bit anyway).

[shifterboy45]

its clear that the majority of people will remain clueless -- looking for answers that exist, but are not readily evident.

in no way, is this rocket science -- but engine operations/dynamics are not clearly understood by most individual, at least until they experiment for themselves. i hope no one is offended by this statement.

trial and error are the best teachers -- maybe choosing the BMW platform to cut teeth on may be a little premature for most.

there are myriad of operational parameters -- all to be contended with at different and/or at the same time -- searching for the right formula for success is a combination of art and science.

[Forcefed3]

Originally Posted by Clap135

Meth will help you reach the max preset timing curve wihtout knocking....assuming you keep it reasonable with boost levels.

But without raising the boost levels you wont gain any power from meth, that is my understanding. Still seems like a good idea though.

[Clap135]

Originally Posted by gbreeE90

But without raising the boost levels you wont gain any power from meth, that is my understanding. Still seems like a good idea though.

Are you saying you want to meth on a bone stock car? CAuse that is overkill. If you chose to get meth, you can most likly get away with up to 16-17psi with little to no mods on the stock preset timing curve. I have done it more 25k

[Forcefed3]

Originally Posted by Clap135

Are you saying you want to meth on a bone stock car? CAuse that is overkill. If you chose to get meth, you can most likly get away with up to 16-17psi with little to no mods on the stock preset timing curve. I have done it more 25k

No, I have FBO, so I am assuming making meth kick in at 11~psi would be beneficial. But then you just have another mod waiting to fail.

[Clap135]

Originally Posted by gbreeE90

No, I have FBO, so I am assuming making meth kick in at 11~psi would be beneficial. But then you just have another mod waiting to fail.

meth can be a huge pita sometimes. Or if you are happy with where you are, you can simply take the steps needed into having a proper timing curve.

[Litos]

Originally Posted by Clap135

Are you saying you want to meth on a bone stock car? CAuse that is overkill. If you chose to get meth, you can most likly get away with up to 16-17psi with little to no mods on the stock preset timing curve. I have done it more 25k

last question:

we all see the "dip", right?

regardless if it's knock or timing retard, will a fmic fix THE DIP !?!?

[Mike@N54Tuning.com]

Originally Posted by Litos

this is the only question that truley needs to be asked.

if there's one uncertainty in this thread, it HAS to be this.......

This has already been discussed. They are preknock or early knock frequencies. The DME intervenes to drop timing instantly to avoid actual knock.

On the maxed out timing curve if you throw enough race gas/meth you can easily max out the stock curve as clap135 did. You can also use flash software to set the maximum advance point very low if you'd like to do that also. But realize then you are just circumventing the learning ability of the DME to adapt timing up during conditions where it would be safe to do so. Whatever floats your boat.

Mike

[Forcefed3]

Originally Posted by Clap135

meth can be a huge pita sometimes. Or if you are happy with where you are, you can simply take the steps needed into having a proper timing curve.

I dont really see any way to change my timing curve.

[Clap135]

Originally Posted by gbreeE90

I dont really see any way to change my timing curve.

Getting a tune that changes is step 1, or getting meth is another option. The last option is relying on what you ahve been doing up to date.

[Clap135]

Originally Posted by Mike@N54Tuning.com

This has already been discussed. They are preknock or early knock frequencies. The DME intervenes to drop timing instantly to avoid actual knock.

On the maxed out timing curve if you throw enough race gas/meth you can easily max out the stock curve as clap135 did. You can also use flash software to set the maximum advance point very low if you'd like to do that also. But realize then you are just circumventing the learning ability of the DME to adapt timing up during conditions where it would be safe to do so. Whatever floats your boat.

Mike

The term preknock doesnt exsist.
As far as setting the timing curve below actual knock, that is simply how tuning works.